(Left to right): COAST PROTECTION BOARD, SOUTH AUSTRALIA; MARTIN WOLF, ICECUBE/NSF; SIMON KING/MINDEN PICTURES

Top stories: liquid sunshine, a galactic messenger on ice, and an ecosystem-altering fence

Ammonia—a renewable fuel made from sun, air, and water—could power the globe without carbon

Researchers are looking to ammonia, the main ingredient in fertilizer, as the next “green” fuel that could power the world without carbon. In that future, scientists would produce ammonia with solar power, water, and air, and convert it into a liquid fuel that could easily be transported around the globe and stored—something that eludes renewable energy today.

Ghostly particle caught in polar ice ushers in new way to look at the universe

If astronomers are right, a ghostly particle that lit up an instrumented swath of ice beneath the South Pole on 22 September 2017 was a messenger from a distant galaxy. The particle was a neutrino, electrically neutral and almost massless, whose path could be traced directly back to the violent cosmic events that created it. Cued by the Antarctic neutrino detector IceCube, an orbiting telescope found that the neutrino likely came from a distant blazar, a bright source of radiation powered by a supermassive black hole.

A fence built to keep out wild dogs has dramatically altered the Australian landscape

A 5000-kilometer-long wire mesh fence built almost a century ago to protect against wild dogs may have altered a piece of Australia’s iconic outback. When scientists compared images from the dingo-full and dingo-free sides of the fence with historical aerial photographs, they discovered that the dingo-free side has more vegetation—and taller dunes. The reason? Foxes and cats—the top predators on the dingo-free side—have likely decimated smaller species that feast on plant seeds and prevent them from taking root.

The ‘Iceman’s’ last meal was a high-fat feast

In 1991, hikers in the Italian Alps stumbled upon a dead body. The man had been dead for about 5300 years, frozen and perfectly preserved by a mountain glacier that had started to melt. Known as Ötzi, or the Iceman, he has become one of the most famous and well-studied natural mummies in the world. Now, researchers have provided a detailed chemical analysis of his last meal and found it was rich in fat.

‘Gene drive’ passes first test in mammals, speeding up inheritance in mice

Researchers have used CRISPR, the genome-editing tool, to speed the inheritance of specific genes in mammals for the first time. Demonstrated in lab-reared insects several years ago, this controversial “gene drive” strategy promises the ability to quickly spread a gene throughout an entire species. The new research aims to create novel strains of lab mice, not wipe out wild populations, and it shows that gene drives work less efficiently in rodents than in insects.